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81.
Nitrous oxide production in high-loading biological nitrogen removal process under low COD/N ratio condition 总被引:20,自引:0,他引:20
Effects of influent COD/N ratio on N2O emission from a biological nitrogen removal process with intermittent aeration, supplied with high-strength wastewater, were investigated with laboratory-scale bioreactors. Furthermore, the mechanism of N2O production in the bioreactor supplied with low COD/N ratio wastewater was studied using 15N tracer method, measuring of reduction rates in denitrification pathway, and conducting batch experiments under denitrifying condition. In steady-state operation, 20-30% of influent nitrogen was emitted as N2O in the bioreactors with influent COD/N ratio less than 3.5. A 15N tracer study showed that this N2O originated from denitrification in anoxic phase. However, N2O reduction capacity of denitrifiers was always larger than NO3(-)-N or NO2(-)-N reduction capacity. It was suggested that a high N2O emission rate under low COD/N ratio operations was mainly due to endogenous denitrification with NO2(-)-N in the later part of anoxic phase. This NO2(-)-N build-up was attributed to the difference between NO3(-)-N and NO2(-)-N reduction capacities, which was the feature observed only in low COD/N ratio operations. 相似文献
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Haruki Matsuo Kazuya Kanasugi Yasuharu Ohgoe Kenji K. Hirakuri Yasuhiro Fukui 《Diamond and Related Materials》2009,18(5-8):1031-1034
Amorphous hydrogenated carbon (a-C:H) films have many excellent properties such as biocompatibility, anti-corrosion, and chemical stability. Therefore, there are many reports on application of a-C:H film as surface modification technique for biomaterials. However, it is difficult to deposit a-C:H film on complex structures such as artificial heart blood pump and synthetic vascular grafts. In our previous work, we have developed an electrode which is adapted to such irregular structures for plasma CVD technique.In this study, a-C:H film was deposited on a synthetic vascular graft inner-wall by r.f. plasma CVD technique with cylindrical electrode. The purpose of such coating is improvement of biocompatibility of the vascular graft. The biocompatibility of the a-C:H film was evaluated by cytocompatibility and plasma protein adhesion. For the a-C:H film deposition, cytocompatibility and protein adsorbent of the vascular grafts were improved for biological response under cell culture with mouth fibroblasts and plasma proteins (albumin, fibrinogen, and globulin), respectively. This study indicates that the a-C:H films coatings is expected to surface modification for medical appliances. 相似文献
84.
Augmentation of lips is a common aesthetic procedure that is mostly performed with alloplastic materials or autologous tissue. Various alloplastic injectable implants have been developed for soft tissue augmentation without surgery. Most biologic materials are resorbed within a few months, fluid silicone may migrate, and autologous fat is not ideal for fine contouring of the lips. The search for a biocompatible, permanent, nontoxic, and biologically inert filler material led to the development of some new materials for subdermal or intradermal implantation. Recently Bioplastique, Artecoll, and Gore-Tex have been well established and recommended by many authors. Although these materials meet most of the characteristics that constitute an ideal injectable prosthetic material, we describe 3 examples of adverse reactions after their implantation into lips. 相似文献
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Photodarkening was investigated in CdS-doped glasses using luminescence and electron spin resonance (ESR). Photodarkening depends on manufacturers of glasses. The main origin of the difference in photodarkening is attributable to the difference in glass composition. 相似文献
88.
LQ Jia M Osada C Ishioka M Gamo S Ikawa T Suzuki H Shimodaira T Niitani T Kudo M Akiyama N Kimura M Matsuo H Mizusawa N Tanaka H Koyama M Namba R Kanamaru T Kuroki 《Canadian Metallurgical Quarterly》1997,19(4):243-253
We have screened the p53 status of 156 human cell lines, including 142 tumor cell lines from 27 different tumor types and 14 cell lines from normal tissues by using functional analysis of separated alleles in yeast. This assay enables us to score wild-type p53 expression on the basis of the ability of expressed p53 to transactivate the reporter gene HIS3 via the p53-responsive GAL1 promotor in Saccharomyces cerevisiae. Of 142 tumor cell lines, at least 104 lines (73.2%) were found to express the mutated p53 gene: 94 lines (66.2%) were mutated in both alleles, three lines (2.1%) were heterozygous, and no p53 cDNA was amplified from seven lines (4.9%). Of the 14 cell lines originating from normal tissues, all the transformed or immortalized cell lines expressed mutant p53 only. Yeast cells expressing mutant p53 derived from 94 cell lines were analyzed for temperature-sensitive growth. p53 cDNA from eight cell lines showed p53-dependent temperature-sensitive growth, growing at 30 degrees C but not at 37 degrees C. Four temperature-sensitive p53 mutations were isolated: CAT-->CGT at codon 214 (H214R), TAC-->TGC at codon 234 (Y234C), GTG-->ATG at codon 272 (V272M), and GAG-->AAG (E285K). Functionally wild-type p53 was detected in 38 tumor cell lines (26.8%) and all of the diploid fibroblasts at early and late population doubling levels. These results strongly support the previous findings that p53 inactivation is one of the most frequent genetic events that occurs during carcinogenesis and immortalization. 相似文献
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90.